Saturday, February 15, 2014

Depression: A Spark of Light in the Dark Night of the Soul? (First Reader, Week 5)

Nesse (2000) suggests that depression, a disorder that
affects millions of people worldwide each year, may in fact confer some
adaptive benefit. He hypothesizes that because depression/low mood promotes
avoidance and withdrawal, it may serve as a useful mechanism in situations in
which taking action may be risky.

However, serious depression (not just “low mood”) is not a
response that can be clicked on or off. It is what occurs when an individual is
exposed to high levels of chronic stress. Many of the physical symptoms of
depression—lethargy, decreased appetite, inability to concentrate, loss of
libido—occur as a result of the long-term suppression or activation of various
systems in the body by stress hormones. Unlike the flight-or-flight response—which
confers immediate action when you’re, say, running away from a lion—chronic
stress results in a state of “learned helplessness.”

Depression, too, carries with it a whole host of nasty
consequences. It increases the likelihood of heart disease, impairs memory
function, and wrecks the immune system. Moreover, depression can last for
years. If depression were truly adaptive, would it not only last for a few
months to a couple years, then cease (bereavement, in fact, does follow this
timeline but is considered distinct from clinical depression)?

Also important to note is the occurrence of suicidal
thoughts and behavior in conjunction with depression. Suicide as a result of
depression is, admittedly, rare. Yet, it nonetheless occurs and is a phenomenon
Nesse notably excludes in his discussion. While suicide does not necessarily
result in a fitness of zero, it is difficult to argue that such behavior is not maladaptive.

Is depression itself maladaptive then? There is strong
evidence that supports the maintenance of certain diseases in the population
for adaptive reasons, the most notable example being sickle-cell anemia.
Carriers for sickle-cell anemia are somewhat more immune to malaria than those
without the allele. However, those carrying both recessive alleles have the
disease.

Low mood, then, could be adaptive with depression being low
mood in its disease state.

Moods and emotions are what allow us to interact with and
experience the world. They are what make the good bits and the not-so-good bits
in life meaningful experiences. Grief and sadness have their place alongside
bliss and delight. Depression, the absence of emotion, can hardly said to be
living at all.

I’ve included below a TEDtalk. It’s given by writer Andrew
Solomon and is one of the best descriptions of the experience of depression I’ve come across.